Freight railroad cars with bulkhead door systems are well known. These railroad cars often need to be taken out of service to repair or replace broken or worn out bulkhead doors and/or related mechanisms. Taking these railroad cars out of service and this repair or replacement process is relatively expensive due to the lost revenue when these railroad cars are out of service and due to the actual cost of the repairs or replacements.
More specifically, bulkhead doors in freight railroad cars are typically large panels which are approximately 8 to 10 inches thick and generally fill the space from the floor to the ceiling and from one side wall to the opposite side wall of the railroad car. These panels move on geared tracks at the top of the railroad car and lock into slots on the floor of the railroad car to restrain the load (i.e., the goods, products, or items) stacked behind the bulkhead doors in the railroad car. The moving parts of these bulkhead door systems tend to wear out due to repeated use as well as due to the constant vibration during movement of the railroad cars. As the bulkhead door systems wear out, the bulkhead doors become harder to move, harder to lock in place, and harder to unlock. After worn to a certain degree, the bulkhead doors and/or related mechanisms must be repaired or replaced.
A further problem with bulkhead door systems in railroad cars is that such systems worked well when the railroad cars were loaded by hand, but tend to be less efficient or not work as well with more current loading processes (such as with loading processes using forklifts, slip sheets, and/or stretch wrap).
An additional problem with bulkhead door systems in railroad cars is their weight. The weight of the bulkhead door systems adds to the overall weight of the railroad cars and thus decreases fuel efficiency and increases overall transportation costs.
Due at least in part to these above described problems with known bulkhead door systems, the number of freight railroad cars with bulkhead door systems is declining.
Various attempts have been made to resolve these problems. Certain railroad cars without bulkhead doors have anchor clips attached to the interior sides of the walls of the railroad cars and adjacent to the doorway openings. These clips are used to secure straps that are in turn used to secure the loads in the railroad cars. Certain types of loads can be adequately secured using just these straps and clips. However, many types of loads can not be adequately secured and protected using just these straps and clips. Certain railroad car systems using materials such as wood and steel to create barrier walls that are secured with straps have also been designed and tested. These systems have problems in use in that they are heavy, costly, difficult to reuse (especially for different types of loads), are not readily recyclable, and decrease the overall fuel efficiency of the railroad cars. Additionally, these systems do not readily absorb forces from the loads while still protecting the loads.
Accordingly, there is a need for a better shock absorption and restraint apparatus for securing loads in railroad cars (and other shipping containers).